Effect of Pre-Treatments and Conversion Coatings on the Corrosion Resistance of Mg Alloys In SBF

Magnesium (Mg) alloys are promising as biodegradable materials and may replace the conventional metal implants if the rapid corrosion rate in the human body can be adequately controlled. One of the most convenient means to protect Mg alloys from corrosion is coating the Mg surface with chemically stable (biocompatible) deposits. The selection of appropriate pre-treatment is essential for subsequent successful surface coatings. In this study, various pre-treatments, such as, acid etching, activation, and passivation are explored on Mg alloys prior to the coating process. Their roles in the coating formation and coating properties are examined in  Minimum Essential Medium (MEM) at physiological conditions. Results demonstrate pretreatment is critical for subsequent coating deposition and controllable biodissolution performance, coating homogeneity, thickness, morphology and adhesion.